The article seems to conflate sex and gender while the study is paywalled so I can't tell how they defined male and female. The study does seem specific to sex and doesn't mention gender at all in the abstract.
Without those definitions it's basically saying "things we grouped a certain way ended up grouped that way" which isn't really a useful result.
Without those definitions it's basically saying "things we grouped a certain way ended up grouped that way" which isn't really a useful result.